(1) Field of the Invention:
The present invention relates to a method of reducing the aromatic primary hydroperoxide content in a hydroperoxide mixture containing an aromatic primary hydroperoxide and an aromatic tertiary hydroperoxide.
(2) Description of the Prior Art:
The method of producing phenols by acid-decomposing hydroperoxides obtained by liquid phase oxidation of alkyl aromatic compounds is industrially valuable as means for preparing phenol, cresol, hydroquinone and resorcin. Furthermore, the above-mentioned hydroperoxides are valuable as the starting compounds for production of peroxides or aromatic alcohols. When a compound having at least two different alkyl groups is used as the alkyl aromatic compound in the above-mentioned liquid phase oxidation, there is often formed a mixture of at least two hydroperoxides having the respective alkyl groups converted to hydroperoxides. If this mixture is directly used as the starting material for the production of phenols, undesirable compounds are formed or the reaction is adversely influenced, resulting in various disadvantages.
For example, in the liquid phase oxidation of cymene, there are formed a primary hydroperoxide based on the oxidation of the methyl group and a tertiary hydroperoxide based on the oxidation of the isopropyl group. It is known that when cresol is prepared from a mixture containing both the hydroperoxides by acid decomposition, formaldehyde formed by acid decomposition of the primary hydroperoxide is condensed with formed cresol to form a resinous product, resulting in reduction of the yield of cresol. In order to eliminate this defect, it has been desired to selectively reduce or remove the primary hydroperoxide in the hydroperoxide mixture or to selectively convert the primary hydroperoxide to a compound having no bad influences. However, there has not been developed an industrial process metting this desire satisfactorily.
For example, a process in which the above-mentioned hydroperoxide mixture is directly reacted with a basic compound is proposed in U.S. Pat. No. 2,728,797 or Japanese Patent Publication No. 12183/77. However, even according to this proposal, it is impossible to sufficiently control decomposition of the tertiary hydroperoxide.